Parse CDR and FWR positions

[Jason Vander Heiden]

We should pull out the CDR and FWR positions and/or sequences from the IMGT and IgBLAST output. Maybe as an optional flag?

We could also just pull out the positions and have a separate script that extracts the regions and optionally translates them, counts mutations, etc.

Also, any reason we parse the JUNCTION instead of the CDR3?

[Namita Gupta]

I added a '--regions' flag to IMGT and IgBLAST parsers that will return FWR and CDR region sequences (IMGT-gapped).